Tribological properties of C/Si-Ni-C composites fabricated by reaction melt infiltration with Si-Ni alloy at lower temperature

Abstract

Carbon fiber-reinforced carbon and silicon carbide dual matrix composites (C/C-SiC) are widely used for braking materials owing to their low density, as well as excellent thermal, mechanical, and tribological properties. However, the presence of residual silicon and the high processing temperatures can adversely affect the fibers, leading to a degradation in the composite's performance. This study proposes a novel approach that utilizes Si-Ni alloy instead of pure Si as the melt for preparing C/Si-Ni-C composites through reaction melt infiltration at a lower temperature. The introduced NiSi and NiSi₂ phases effectively replace some of the brittle phases, such as SiC and C, thereby enhancing the overall performance of the composites. The mechanical, thermal and tribological properties of the C/Si-Ni-C composite are investigated and compared with those of composites prepared using pure Si. The results indicate that the thermal conductivity of C/Si-Ni-C reaches 49.38 W/m·K, which is 62 % higher than that of pure Si. Additionally, the wear rate is significantly reduced to 0.77 × 10⁻⁵ mm³ N⁻¹m⁻¹, showing a 75 % decrease compared to pure Si when tested under a sliding speed of 0.50 m/s and a load of 30 N. The coefficient of friction of C/Si-Ni-C composites remains stable and can be adjusted. Furthermore, the prepared C/Si-Ni-C composites exhibit anisotropic properties when the steel ball slides perpendicular to or parallel to the fiber alignment.